Improved Subthreshold Characteristics of Epi-Silicon FinFET via Fin Surface Passivation Technologies

As demand for advanced integrated circuits (ICs) continues to grow, fin field-effect transistors (FinFETs) have remained highly influential in the IC market because of their mature fabrication process and powerful driving capabilities. However, the ion bombardment that occurs during the reactive ion etching (RIE) process used to form the fin structure increases the fin’s surface roughness and results in a high interfacial state density ( D it ), which hinders further improvement in the subthreshold swing (SS) of FinFETs. To overcome this issue, this study proposes two oxidative trimming methods for use on the fin structures to improve their interface quality. It is found that conventional thermal oxidation and low-temperature oxidation processes reduced the channel D it by 73.31% vs 71.17%, respectively. Furthermore, the corresponding SS values of the device improved to 72.76 and 71.72 mV dec −1 , respectively. The technical solutions proposed in this paper represent a promising approach for performance optimization of FinFETs and other advanced devices.